DE2550796C3 - Process for the preparation of stable dispersions - Google Patents

Description

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Production of polyurethane plastics.

The invention relates to an improved process for producing finely divided, stable and relatively low-viscosity dispersions of polyisocyanate polyaddition products in compounds containing hydroxyl groups and the use of such dispersions as starting components for the production of polyurethane plastics.

Diisocyanate polyaddition products dispersed in polyethers or polyesters are known. According to the teaching of DE-AS 1168 075, diisocyanates are reacted with bifunctional primary alcohols in a polyether or polyester (molecular weight 500-3000) as a dispersing medium, whereby the polyether or polyester contains at least two (exclusively secondary) hydroxyl groups in the molecule. According to DE-AS 12 60 142, compounds containing NCO and NH groups are polyadded "in situ" in a polypropylene glycol ether as a dispersant. The processes mentioned produce dispersions of polyurethanes, polyureas or polyhydrazodicarbonamides in polyvalent, high molecular weight compounds containing hydroxyl groups, which are recommended as thickening agents for textile or dyeing auxiliaries due to their high viscosity even at a low solids content.

For example, a 10(20)% polyhydrazodicarbonamide dispersion in a polypropylene glycol ether according to DE-AS 12 60 &Idigr;42 has a viscosity of over 10,000 (200,000) cP at 25° C. This corresponds to more than 10(200) times the viscosity of the pure dispersant. When attempting to produce a 40% dispersion, the reaction mixture solidifies before the polyaddition is complete. The high viscosities, even with relatively low solids contents, severely limit the possible uses of the process products, since in many areas of application it is not possible to use the usual dosing devices for dosing them. In the manufacture of polyurethane foams, for which such dispersions can be used according to an older proposal, the viscosities of the starting materials must, for example, be below 2500 cP if the high-pressure machines predominantly used are used.

According to another older proposal, it is possible to produce largely water-free, relatively low-viscosity dispersions of polyureas and/or polyhydrazodicarbonamides in polyethers containing hydroxyl groups if the polyaddition reaction is allowed to run continuously in flow mixers. The process has the disadvantage that a relatively complex dosing and mixing technique is required, which is uneconomical for normal production batches; in addition, in some cases of higher solids concentration, the removal of the reaction heat can cause considerable difficulties.

It was recently found that

stable dispersions with the desired low viscosity can also be produced in simple stirring apparatus if the polyaddition is carried out "in situ" in a mixture of hydroxyl-containing compounds and a large amount of water and, if necessary, the water is removed by distillation after the polyaddition reaction.

A water content of 10, 15 or 20% by weight (based on the total amount of polyether and water), for example, increases the viscosity of a polyalkylene ether glycol at 25°C to 4, 8 or over 50 times the original value (3500, 7300 or over 50,000 cP). If the water content is increased further, the solution or emulsion initially formed often separates with phase separation. Both the strong increase in viscosity and the separation must have made the expert consider the use of water, which could also interfere as an additional reaction partner in the isocyanate polyaddition reaction, unsuitable for the industrial production of low-viscosity polyisocyanate polyaddition products in compounds containing hydroxyl groups.

The invention therefore relates to a process for the »in situ« production of stable dispersions of polyisocyanate polyaddition products in compounds containing hydroxyl groups as dispersants by reacting
(1.) organic polyisocyanates with (2.) at least difunctional primary and/or secondary amino group-containing compounds with a molecular weight of 60-10 000 and/or

Hydrazines with a molecular weight of 32-500 and/or

Hydrazides with a molecular weight of 90-10000 and/or

at least difunctional compounds containing primary hydroxyl groups with a molecular weight of 62-400 in

(3.) compounds containing at least one hydroxyl group and having a molecular weight of 62 16000

where the compounds of group (3) have secondary hydroxyl groups if compounds of group (2) are those with primary hydroxyl groups, characterized in that the reaction components are reacted in the presence of 7-35% by weight of water, or when using strongly hydrophilic alcohols in the presence of 4-35% by weight of water, based on the reaction mixture (including water), and optionally the water is subsequently removed in a manner known per se.

According to the invention, it is preferred to use polyamines and/or hydrazines and/or hydrazides as component (2).

According to a particular embodiment of the process according to the invention, monoisocyanates and/or primary or secondary monoamines and/or monohydrazides can be used as reaction components (1 or 2) in order to set a specific molecular weight. It is also possible to add hydroxyalkylamines to the polyaddition reaction for this purpose. In this way, polyurea or polyhydrazodicarbonamide particles with reactive groups are also obtained.

It is also possible to use proportionately emulsifying and dispersion-stabilizing substances such as polyethers containing amine, semicarbazide or hydrazide groups.

The invention also relates to stable dispersions containing 10 to 60% by weight of solids of polyureas or polyhydrazodicarbonamides in hydroxyl compounds with a molecular weight between 6? and 400 or in hydroxyl compounds which consist of more than 30% by weight, preferably more than 50% by weight, of polyesters and/or polyesteramides and/or polycarbonates with a molecular weight between 400 and 12,000, preferably 800 to

&iacgr;&ogr; 8000, exist.

Dispersants, i.e. the outer, coherent phase, in the sense of the invention are 1 to 8, preferably 2 to 6, particularly preferably 2 to 4 alcohols containing primary and/or secondary hydroxyl groups and having a molecular weight of 62-16,000, preferably 62 to 12,000, particularly preferably 106 to 8000.

These include, on the one hand, low molecular weight alcohols or glycols with a molecular weight between 62 and about 400, which may also contain ether, thioether or ester bonds, and, on the other hand, polyesters, polyethers, polythioethers, polyacetals, polycarbonates and polyester amides with molecular weights of more than 400, as are known per se for the production of polyurethanes.

Suitable low molecular weight dispersants are monoalcohols such as butanol, 2-ethylhexanol, amyl alcohol and ethylene glycol monoethyl ether, as well as diols commonly used in polyurethane chemistry as chain extenders or crosslinking agents.

len or triols, such as propylene glycol-(1,2) and -(1,3), butylene glycol-(1,4) and -(2,3), hexanediol-(1,6), octanediol-(1,8), neopentyl glycol, 1,4-bis-hydroxymethylcyclohexane, 2-methyl-l,3-propanediol, glycerin, trimethylolpropane, hexanetriol-C 1,2,6), butanetriol-(1,2,4)

or trimethylolethane, in particular glycols with a hydrophilic character, such as ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol and polyethylene glycols with a molecular weight of up to 400. In addition, according to the invention, compounds such as dipropylene glycol, polypropylene glycols with a molecular weight of up to 400, dibutylene glycol, polybutylene glycols with a molecular weight of up to 400, thiodiglycol and castor oil can also be used as dispersants, as well as esterdiols of the general formula

and
so HO-(CH ₂ ),-O-CO-R-CO-O-(CH ₂ ) ₍ -OH

in which

R is an alkylene or arylene radical having 1-10, preferably 2-6 C atoms,
&khgr; = 2—6and
y =3-5
mean,

e.g. δ-hydroxybutyl-s-hydroxy-caproic acid ester, ω-hydroxyhexyl-γ-hydroxybutyric acid ester, adipic acid bis(|3-hydroxyethyl) ester and terephthalic acid bis(j3-hydroxyethyl) ester; and

Diolurethanes of the general formula

O-CO-NH-R'-NH-CO-O-(CHj) ₁ -OH

in the

R' is an alkylene, cycloalkylene or arylene radical with

2-15 , preferably 2-6 C atoms and &khgr; a number between 2 and 6

represent,

HO-(CH ₂ J ₁ -N-CO-NH -R"-NH-CO-

R'"
in the

R". an alkylene, cycloalkylene or arylene radical with 2-R'" = H or CH ₃ and
&khgr; =2or3

mean,

e.g. 4,4'-diphenylmethane-bis-(/?-hydroxyethyl urea) or the compound

_{/ CH3} - _CH3

e.g. l,6-hexamethylene-bis-(/?-hydroxyethylurethane)
or

4,4'-Diphenylmethane-bis-(<5-hydroxybutylurethane);
or

Diolureas of the general formula
-N-(CH ₂ ),- OH

R'"

-15, preferably 2&mdash;9, C atoms,

HO-CH,-CH,-NH-CO-NH-<H

CH ₃ CH ₂ -NH-CO-NH-CH ₂ -CH ₂ -Oh

Particularly suitable among the di- and trivalent low molecular weight alcohols are those which, optionally as a mixture or with the use of higher molecular weight alcohols, are liquid at temperatures below 50°C.

The higher molecular weight polyesters containing hydroxyl groups that can be used as dispersants are, for example, reaction products of polyhydric, preferably dihydric and optionally additionally trihydric alcohols with polyhydric, preferably dihydric, carboxylic acids. Instead of the free polycarboxylic acids, the corresponding polycarboxylic anhydrides or corresponding polycarboxylic esters of lower alcohols or mixtures can also be used to produce the polyesters. The polycarboxylic acids can be aliphatic, cycloaliphatic, aromatic and/or heterocyclic in nature and can optionally be substituted and/or unsaturated, for example by halogen atoms. Examples of these include:

Succinic acid, adipic acid, suberic acid, azelaic acid, sebacic acid, phthalic acid, isophthalic acid, trimellitic acid, phthalic anhydride,

Tetrahydrophthalic anhydride, hexahydrophthalic anhydride, tetrachlorophthalic anhydride, endomethylenetetrahydrophthalic anhydride, glutaric anhydride, maleic acid, maleic anhydride, fumaric acid, dimeric and trimeric fatty acids,

such as oleic acid, optionally mixed with monomeric fatty acids,

1 cic-piitiiaiaaui wliiii\*iiijtix~.3vn»i uhu

Terephthalic acid bis-glycol ester.

Examples of polyhydric alcohols include:

Ethylene glycol,

Propylene glycol-(1,2) and -(U), butylene glycol-(1,4) and -(2,3),

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55

60

65 hexanediol-(l.6), octane-diol-(l.8),
Neopentyl glycol,
1,4-bis-hydroxymethylcyclohexane,
2-methyl-l 3-propanediol, glycerin,
Trimethylolpropane, hexanetriol-(1,2,6),
Butanetriol-(l,2,4),trimethylolethane,
Triethylene glycol, Tetraethylene glycol,
Polyethylene glycols, dipropylene glycol,
Polypropylene glycols, dibutylene glycol and
Polybutylene glycols

The polyesters can have a proportion of terminal carboxyl groups. Polyesters made from lactones, e.g. ε-caprolactam or hydroxycarboxylic acids, e.g. ω-hydroxycaproic acid, can also be used.

The polyethers with higher molecular weight preferred as dispersants according to the invention are prepared in a manner known per se by reacting starter compounds with reactive hydrogen atoms with alkylene oxides, such as ethylene oxide, propylene oxide, butylene oxide, styrene oxide, tetrahydrofuran or epichlorohydrin or with any mixtures of these alkylene oxides. In many cases, those polyethers which predominantly have primary OH groups are preferred.

Suitable starter compounds with reactive hydrogen atoms are, for example:

Water, methanol, ethanol, ethylene glycol,
Propylene glycol-(1,2) or -(13),
Butylene glycol-(1,4) or -(2,3),
Hexanediol-(l,6),octanediol-(l,8),
Neopentyl glycol,
M-bis-hydroxymethylcyclohexane,
2-methyl-l,3-propanediol, glycerin,
Trimethylolpropane, Hexantnol-(1,2,6),
Butanetriol-(1,2,4),trimethylolethane,
Pentaerythritol, mannitol, sorbitol, methyl glycoside,
Cane sugar, phenol, isononylphenol,
Resorcinol, hydroquinone,
1,2,2- or l,l,3-tris-(hydroxyphenyl)-ethane,
ammonia, methylamine, ethylenediamiri,

Tetra- or hexamethylenediamine,

Diethylenetriamine, ethanolamine,

diethanolamine, triethanolamine,

Aniline, phenylenediamine,

2,4- and 2,6-diaminotoluene and

polyphenyl-polymethylene-polyamines,

^As they are obtained by aniline-formaldehyde condensation. Resinous materials of the phenol and resol type can also be used as starters.

Among the polythioethers, the condensation products of thiodiglycol with itself and/or with other glycols, dicarboxylic acids, formaldehyde, aminocarboxylic acids or amino alcohols are particularly mentioned. Depending on the co-components, the products are polythio mixed ethers, polythioether esters or polythioether ester amides.

Examples of suitable polyacetals are compounds that can be prepared from glycols such as diethylene glycol, triethylene glycol, 4,4'-dioxethoxy-diphenyldimethylmethane, hexanediol and formaldehyde. Polyacetals suitable for the invention can also be prepared by polymerizing cyclic acetals.

Suitable polycarbonates containing hydroxyl groups are those of the type known per se, which can be produced, for example, by reacting diols such as propanediol-(U), butanediol-(1,4) and/or hexanediol-(1,6), diethylene glycol, triethylene glycol or tetraethylene glycol with diaryl carbonates, e.g. diphenyl carbonate, or phosgene.

Polyesteramides and polyamides include, for example, the predominantly linear condensates obtained from polyvalent saturated and unsaturated carboxylic acids or their anhydrides and polyvalent saturated and unsaturated amino alcohols, diamines, polyamines and their mixtures.

Of course, according to the invention, as already mentioned above, mixtures of the high- and low-molecular dispersants mentioned can also be used.

According to the invention, preference is given to those dispersants which do not contain any labile groups (e.g. ester groups) which can be destroyed by hydrolysis or aminolysis during the process according to the invention. Such compounds are expediently only added to the finished dispersion after the polyaddition reaction has been completed.

The hydroxy compounds or mixtures thereof used as dispersants according to the invention are to be selected so that they (in a mixture with the water added according to the invention, optionally OH or preferably NH compounds and optionally an inert solvent) are liquid at the reaction temperature, i.e. are present as a solution or emulsion. The viscosity at the reaction temperature should generally be less than 20,000 cP, preferably less than 5,000 cP, so that the usual stirring and mixing equipment can be used.

If inert solvents are used, they should preferably be those that can be distilled off with water as an azeotrope, for example benzene and toluene.

According to the invention, the components that are reactive towards isocyanates when preparing the dispersions are primarily polyamines, hydrazines and hydrazides. Suitable polyamines are two

and/or polyvalent, primary and/or secondary, aliphatic, araliphatic, cycloaliphatic and aromatic amines, e.g.

Ethylenediamine, 1,2- and 1,3-propylenediamine,
tetramethylenediamine, hexamethylenediamine,
Dodecamethylenediamine,Trimethyldiaminohexane, N,N'-dimethylethylenediamine,
2,2'-bis-amino-propyl-methylamine,

higher homologues of ethylenediamine, such as

Diethylenetriamine, triethylenetetramine and
Tetraethylenepentamine,

Homologues of fropyiendiamine, such as

Dipropylenetriamine, Piperazine,
N.N'-Bis-aminoethylpiperazine.Triazine,
4-aminobenzylamine,4-aminophenylethylamine,
1 -Amino-S^S-trimethyl-S-arninomethylcyclohexane,

4,4'-diaminodicyclohexylmethane and -propane,
1,4-diaminocyclohexane,
phenylenediamines, naphthylenediamines,

Condensates of aniline and formaldehyde, toluenediamines, bis-aminomethylbenzenes and the derivatives of the aromatic amines mentioned monoalkylated on one or both nitrogen atoms. The polyamines generally have a molecular weight of 60-10,000, preferably 60-3,000, particularly preferably 60-1,000.

Hydrazines include hydrazine and mono- or ν,ν'-disubstituted hydrazines, where the substituents can be Q-Q alkyl groups, cyclohexyl groups or phenyl groups. The hydrazines generally have a molecular weight of 32 to 500.

Hydrazine itself is preferred.

Hydrazides include the hydrazides of di- or polyvalent carboxylic acids, such as carbonic acid, oxalic acid, malonic acid, succinic acid, adipic acid, sebacic acid, azelaic acid, maleic acid, fumaric acid, phthalic acid, isophthalic acid, terephthalic acid, and also the esters of hydrazine monocarboxylic acid with di- or polyvalent alcohols and phenols, such as ethanediol, propanediol-(1,2), butanediol-(1,2), -(1,3) and -(1,4), hexanediol, diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol and hydroquinone, as well as the amides of hydrazine monocarboxylic acid (semicarbazides) with, for example, the di- and polyamines mentioned above. The hydrazides generally have a molecular weight of 90-10,000, preferably 90-3,000, particularly preferably 90-1 OuO.

The above-mentioned amines and hydrazines are used in the form of their dilute aqueous solutions or -mixed with the dispersant- diluted with the required amount of water

Aliphatic, cycloaliphatic, araliphatic, aromatic and heterocyclic polyisocyanates, as described by W. Siefken in Justus LJebigs Annalen der Chemie, 562, pages 75 to 136, for example, can also be used as starting components according to the invention.

Ethylene diisocyanate,

1,4-Tetramethylene diisocyanate

1,6-hexamethylene diisocyanate,

l.^-Dodecane diisocyanate,

Cyclobutane-1,3-diisocyanate,

Cyclohexane-13- and -1,4-diisocyanate

and any mixtures of these isomers,

1 -Isocyanato-SßrS-trimethyl-S-isocyanatomethyl-cyclohexane

(DE-AS 12 02 785, US-PS 34 01 190),
2,4- and 2,6-hexahydrotoluene diisocyanate
and any mixtures of these isomers,
Hexahydro-1,3- and/or j0

-1,4-phenylene diisocyanate,
Perhydro-2,4'- and/or
^^'-diphenylmethane diisocyanate,

.,3- and 1,4- phenylene diisocyanate,

2,4- and 2,6-toluene diisocyanate and any mixtures of these isomers,
Diphenylmethane-2,4'- and/or -4,4'-diisocyanate,
Naphthylene US diisocyanate,
Triphenylmethane 4,4',4"-triisocyanate,
polyphenyl polymethylene polyisocyanates,

as obtained by aniline-formaldehyde condensation and subsequent phosgenation and described, for example, in GB-PS 8 74 430 and 8 48 671, m- and p-isocyanatophenyl-sulfonyl-isocyanates according to US-PS 34 54 606, perchlorinated aryl polyisocyanates, as described, for example, in DE-AS 1157 601 (US-PS 32 77 138), polyisocyanates containing carbodumide groups, as described in DE-PS 10 92 007 (US-PS 31 52 162), diisocyanates, as described in US-PS 34 92 330, polyisocyanates containing allophanate groups, as described, for example, in DE-AS 1157 601 (US-PS 32 77 138), B. in GB-PS 9 94 890, BE-PS 7 61 626 and the published NL patent application 7102 524, polyisocyanates containing isocyanurate groups. as described e.g. in US-PS 30 01 973, in DE-PS 10 22 789,12 22 067 and 10 27 394 and in DE-OS 19 29 034 and 20 04 048, polyisocyanates containing urethane groups, as described e.g. in BE-PS 7 52 261 or in US-PS 33 94 164, polyisocyanates containing acylated urea groups according to DE-PS 12 30 778, polyisocyanates containing biuret groups, as described e.g. B. in DE-PS 11 01 394 (US-PS 31 24 605 and 32 01 372) and GB-PS 8 89 050, polyisocyanates produced by telomerization reactions, as described for example in US-PS 36 54 106, polyisocyanates containing ester groups, as mentioned for example in GB-PS 9 65 474 and 10 72 956, in US-PS 35 67 763 and in DE-PS 12 31 688, reaction products of the above-mentioned isocyanates with acetals according to DE-PS 10 72 385 and polyisocyanates containing polymeric fatty acid residues according to US-PS 34 55 883.

It is also possible to use the distillation residues containing isocyanate groups that accrue during the industrial production of isocyanates, optionally dissolved in one or more of the aforementioned polyisocyanates. It is also possible to use any mixtures of the aforementioned polyisocyanates.

As a rule, particularly preferred are the technically easily accessible polyisocyanates, e.g. 2,4- and 2,6-toluene diisocyanate, as well as any mixtures of these isomers (»TDI«), polyphenyl-polymethylene polyisocyanates, as produced by aniline-formaldehyde condensation and subsequent phosgenation (»crude MDI«) and polyisocyanates containing carbodiimide groups, urethane groups, allophanate groups, isocyanate groups, urea groups or biuret groups (»modified polyisocyanates«).

Of course, so-called prepolymers can also be used as the isocyanate component according to the invention, i.e. reaction products of low and/or high molecular weight compounds with OH and/or NH groups (e.g. those of the type mentioned above) with an excess of the monomeric polyisocyanates described above.

The process according to the invention also allows the partial or exclusive use of isocyanates or amines, hydrazines or hydrazides, whose functionality is greater than two. It is surprising that the reaction according to the invention of such higher-functional compounds in the dispersant containing hydroxyl groups does not lead to solid or at least very highly viscous reaction products, but also to finely divided, low-viscosity dispersions.

The polyaddition products dispersed in compounds containing hydroxyl groups prepared by the process according to the invention can, as already mentioned, also be modified by the proportional use of monofunctional isocyanates, amines, hydrazine derivatives or ammonia.

For example, the average molecular weight of the polyaddition products can be adjusted as desired by incorporating such monofunctional compounds. When using alkanolamines with primary or secondary amino groups, polyureas and polyurea polyhydrazodicarbonamides can be constructed that have free hydroxyl groups. The introduction of other groups, such as ester groups, longer aliphatic radicals, tertiary amino groups, active double bonds, etc. is also possible if appropriately substituted mono- or diamines or isocyanates are also used.

Suitable monofunctional isocyanates are, for example, alkyl isocyanates, such as methyl, ethyl, isopropyl, isobutyl, hexyl, lauryl and stearyl isocyanate, chlorohexyl isocyanate, cyclohexyl isocyanate, phenyl isocyanate, tolyl isocyanate, 4-chlorophenyl isocyanate and diisopropylphenyl isocyanate

Examples of monoamines include alkyl and dialkylamines with Ci-Ci8-alkyl groups, cycloaliphatic amines, such as cyclohexylamine and homologues, aniline and N-alkylanilines, as well as aniline derivatives substituted on the benzene nucleus, alkanolamines, such as ethanolamine, diethanolamine, propanolamine, dipropanolamine, butanolamine and dibutanolamine, as well as diamines with a tertiary and a primary or secondary amino group, such as ν,ν-dimethylethylenediamine and N-methylpiperazine. Examples of monofunctional hydrazine derivatives and hydrazides include: B. �Ngr;,�Ngr;-dialkylhydrazines, the hydrazides of monocarboxylic acids, hydrazinemonocarboxylic acid esters of monofunctional alcohols or phenols, as well as semicarbazides, such as methyl, ethyl, propyl, butyl, hexyl, dodecyl, stearyl, phenyl and cyclohexyl semicarbazide come into consideration

The molecular weight of the polyaddition products dispersed in hydroxyl compounds prepared according to the invention is determined by the ratio between the polyamine, hydrazine or hydrazide on the one hand and the polyisocyanate on the other hand

(or by the monofunctional compounds that may be used). It is particularly preferred to react approximately equivalent amounts of isocyanates and OH-functional or preferably NH-functional compounds in the dispersant containing hydroxyl groups. (Chain extenders containing primary hydroxyl groups are reacted in a dispersant that only contains secondary hydroxyl groups) It is also possible to work with a limited excess of isocyanate, but with increasing excess products with a relatively higher viscosity are obtained, since the excess of polyisocyanate reacts with the dispersant. In contrast, a large excess of low molecular weight chain extenders, for example amine, hydrazine or hydrazide, is possible without increasing the viscosity, whereby polyaddition products with reactive end groups and limited molecular weight are obtained. In general, an equivalent ratio of polyisocyanate/chain extender between 0.50 and 1.50 is maintained, preferably between 0.90 and 1.10, particularly preferably approximately equivalent amounts are used.

When polyisocyanates are reacted with polyamines or hydrazines or hydrazides in the presence of compounds containing hydroxyl groups, the reaction between NCO and NH groups is strongly favored, but depending on the reaction conditions, the OH groups of the dispersant also participate in the reaction to a certain extent. This reaction produces polyurea and/or polyhydrazodicarbonamide chains that are chemically linked to the mono- or preferably polyalcohol that serves as the dispersant. Such end groups presumably have a dispersing effect on the solid particles. The proportion of this participation of the OH groups in the polyaddition reaction depends particularly on the temperature control and the water content. If too many high molecular weight polyol molecules react with the polyisocyanates, highly viscous dispersions are obtained. This is evidently the case with the procedure according to DE-AS 12 60 142. On the other hand, if the proportion of co-reacting polyol molecules is too low, there is a risk that the larger particles of the dispersions formed will not be stable but will sediment. The process according to the invention surprisingly allows the proportion of the NCO/OH reaction to be adjusted so that, on the one hand, fine-particle dispersions with the desired low viscosity are formed, but on the other hand, coarser parts of the dispersions are still so stable that they do not sediment even after long storage, even at elevated temperatures.

When using low-viscosity polyethers containing only secondary OH groups or low-reactivity (aliphatic) isocyanates, the proportion of co-reacting polyol molecules may be too low to achieve a stable dispersion in some cases of NCO/NH polyaddition. In these cases, it is advisable to include substances that have an emulsifying effect and thus increase the stability of the dispersion in the polyaddition reaction. Such substances are, for example, linear polyethers with an average molecular weight of 300-4000, which contain NCO groups or amino or hydrazide groups at both or preferably only at one chain end.

For example, it is possible to prepare small amounts of isocyanate adducts of diols of the general formula

R"'

R'"

HO-CH -CH ₂ -N-CH ₂ -CH-OH

CO-NH-R-NH-CO-OZ-CH ₂ -CH-Ot-CH ₂ -CH ₂ -XR'

^RIV

50

as an emulsifying agent, in which

R represents a divalent residue such as

by removing the isocyanate groups from a diisocyanate of molecular weight

112&mdash;1000 is obtained.
X stands for oxygen or - NR" -,

R' and R" are the same or different and for

monovalent hydrocarbon residues with

1 &mdash; 12 carbon atoms,
R"' is hydrogen or a monovalent

Hydrocarbon residue with 1&mdash;8 carbon atoms

R ^IV is a hydrogen atom or — CH3 and

&pgr; is an integer of 4&mdash;89

The preparation of such emulsifying diols is described, for example, in DE-OS 23 14512.

Modified polyethers with a dispersing effect that may be used in accordance with the invention are, in addition to those of the above general formula, the addition products of excess di- and/or polyisocyanates, as mentioned above by way of example, with mono- and/or bifunctional hydroxyl polyethers with an average molecular weight of 300-4000, which may have been freed of unreacted free isocyanate by thin layers. If necessary, such isocyanate prepolymers can also be reacted with the excess free isocyanate to form allophanate isocyanates. It is also possible to convert the addition products containing isocyanate end groups with excess diamines or hydrazine, for example according to DE-AS 11 22 254 or 11 38 200, into polyethers containing amino or semicarbazide end groups.

Polyethers containing amino end groups, such as those that can be produced using the processes of US Pat. No. 3,155,278 or DE-AS 1,215,373, can also be used as dispersing agents according to the invention.

Finally, hydroxyl polyethers can also be converted into chloroformic acid esters using phosgene and these can then be reacted with excess diamine or hydrazine. As already mentioned, polyethers that only have an NCO or NHr group at one end of the chain are preferred as dispersing agents.

However, the dispersions which are particularly preferred according to the invention and have a solids content of approx. 10-60 wt.-% are generally only added up to approx.

15% by weight, preferably up to 3% by weight (based on the total amount of polyol and solids), of the modified polyether with a dispersing effect is added. (For dispersions with a higher or lower solids content, more or less of the dispersing agent is used accordingly.)

According to a less preferred variant of the process according to the invention, it is also possible to react compounds of the above-mentioned type with 2 or more primary hydroxyl groups and a molecular weight of 62 to 400 (optionally together with monohydric primary alcohols) with polyisocyanates to form polyurethane dispersions. However, it must be noted that in this case only dispersants can be used which carry exclusively secondary hydroxyl groups and preferably have a molecular weight of more than about 500, so that a selective reaction of the polyisocyanate with the primary hydroxyl compounds is guaranteed.

The amount of water present during the polyaddition reaction according to the invention is of crucial importance both in terms of particle size, particle size distribution and final viscosity of the dispersion. Several factors must be taken into account simultaneously: the viscosity and hydrophilicity or hydrophobicity of the dispersant containing alcoholic groups used, the solubility or emulsifiability of the starting components intended for the isocyanate polyaddition, the solids content of the resulting dispersion and the temperature control. In addition, the order and type of addition can also have an influence. As the water content increases, as explained above by way of example, a significant increase in viscosity occurs, particularly with slightly hydrophilic, higher molecular weight dispersants. This effect is intensified as the polyaddition progresses in water-diluted alcohol. This limits the maximum amount of water used in all cases ·*&ogr; Good miscibility of the reaction mixture in the presence of water must be ensured during the polyaddition reaction or during the subsequent water distillation. In general, less than 35% by weight, but at least about 7% by weight of water, based on the total amount of the reaction mixture, is added (the higher the desired solids content of the dispersion, the more water should be used). The optimum amount of water is that which, on the one hand, enables the lowest possible final viscosity of the dispersions produced according to the invention and, on the other hand, saves the need to distill unnecessarily large amounts of water. In many cases, the preferred amount of water is a total of 10-25% by weight, based on the reaction mixture. When using highly hydrophilic alcohols, smaller amounts of water, starting at 4% by weight, can also be used. _.

In order to achieve the lowest possible final viscosity, it is also advantageous to choose the reaction temperature as high as possible at the beginning of the polyaddition reaction, ideally close to the boiling point of water.

By using stirred tanks with reflux condensers, the heat of reaction in the highly exothermic isocyanate reaction can be easily removed by boiling under reflux. At the same time, any adducts that may form in the gas phase above the liquid reaction mixture are continuously flushed from the water into the liquid phase in "statu nascendi" and distributed in fine dispersion.

The dispersant can be mixed with the reaction components in various ways. In the simplest case, the dispersant containing hydroxyl groups, the required amount of water and the NH compound (or the primary hydroxyl compound) are placed in a stirred tank apparatus, heated with stirring to, for example, 70-90°C and the component containing isocyanate groups is allowed to flow in so quickly that the reaction mixture boils vigorously under reflux. When producing dispersions with a high solids content, it is advantageous to introduce the polyisocyanate (mixture) into the lower third of the liquid mixture. In suitable tank apparatus, the reaction temperature can be increased to 105-115 ⁰ C if necessary by applying a slight excess pressure. When the isocyanate groups have reacted completely, the water and any inert solvent present are distilled off under reduced pressure and the dispersion is drained through a sieve. Of course, in many cases the optionally aqueous solution of the NH compound and the polyisocyanate can also be added simultaneously to the dispersant diluted with water. However, an excess of isocyanate must be avoided. Part of the heat of reaction can also be consumed by mixing the polyisocyanate at room temperature, for example with part of the alcohol used as a dispersant, immediately before addition. If it is desired to carry out the process according to the invention continuously, for example in the case of large-scale production of more than ^{1000 moto, the dispersant, the reaction components and the water can be continuously metered in in continuous mixers. Because of the highly exothermic reaction with increasing solids content and the resulting increase in vapor pressure, the residence time must be so short that the reaction temperature in the premixer does not exceed 100 °} C if possible. When producing a 40% dispersion, the flow rate is not significantly above 1-3 seconds. The premixed reaction mixture is introduced into a stirring vessel and, after a residence time of 20-30 minutes, is pressed into a vessel for distillation of the water.

Water distillation can also be carried out at a later time, but the dispersions obtained in this way have a higher viscosity.

In practice, the discontinuous kettle process and immediate water distillation are preferred to achieve a particularly low viscosity because of their extraordinary simplicity, safety in the reaction process and reproducibility.

The finished dispersion can of course contain the water content required for later processes, for example for the production of polyurethane foams

The concentration of the polyaddition products in the dispersant containing hydroxyl groups can vary widely, but is generally between 1 and 60% by weight, particularly between 5 and 50% by weight. Depending on their concentration, the

Dispersions prepared according to the invention have viscosities of up to 80,000 cP, preferably up to 40,000 cP, at 25° C. After dilution to 10% by weight solids content, the viscosity is generally less than 2500, preferably less than 1500 cP at 25° C. It is a particular advantage of the process according to the invention that in many cases the dispersions prepared in very high concentrations have a relatively lower viscosity after dilution with the same dispersant than comparable products prepared directly with a lower solids content.

In tank stirrer apparatus with reflux condenser, as explained above, dispersions with a surprisingly high solids content (up to over 50%) can be produced cost-effectively according to the invention, despite the highly exothermic reaction of NCO with NH groups. Since the dispersions are usually used with a solids content of around 10% by weight for the production of polyurethane plastics, it is possible to use alcohols containing hydroxyl groups, for example polyester, in large proportions by weight as a mixing component, which would possibly undergo partial reactions (e.g. hydrolysis or aminolysis) with water or NH compounds at the temperatures used to produce the dispersion. For example, a finished 40% polyhydrazodicarbonamide dispersion in polyether can be used to obtain: For example, by stirring in the same or three times the amount of polyester (see Example 7), a 20(10)% dispersion with a polyether/polyester weight ratio of 3:5 (1:5) and a viscosity that is only slightly higher than the viscosity of the pure polyester or even lower is obtained.

Surprisingly, such dispersions in polyol mixtures are stable even when the polyether and the polyester are not miscible with each other under otherwise identical conditions. In these cases, the dispersed polyurethane solid evidently acts as an emulsifier, which prevents the system from separating into two phases even after a long storage period. This is another important advantage of the process according to the invention, since such stabilized polyester/polyether systems can be used to produce new types of polyurethane plastics that are not accessible by other means.

The use of high molecular weight, hydroxyl group-containing polyethers as dispersants in the process according to the invention, as already mentioned, enables a particularly economical, gentle and varied technical production of dispersions with high solids concentrations, which can optionally serve as a "masterbatch". However, the use of polyethers has another major advantage: In the large-scale production of polyethers, aqueous crude polyether suspensions with a water content of 8-12% by weight are usually obtained, in which 0.3-1% by weight of alkali sulfates are dissolved and an additional 1-3% by weight of toluene is suspended. Preferably, such a "crude polyether suspension" is first freed of water and toluene by distillation under reduced pressure to a residual amount of 0.4-1% by weight. The alkali sulfates precipitate and can be isolated using sponge filters.

The sulfate-free polyether, which contains 0.5-1% by weight of water, is largely freed of residual water by thin layers, so that the water content of the purified polyether commercial product is less than 0.5% by weight. For the process according to the invention, however, it is not necessary to use a highly purified, practically water-free polyether. Rather, it is sufficient to use the crude polyether precursors either before the thin layers or, which is particularly advantageous, the "crude polyether suspension" (with about 10% water, alkali sulfate and toluene content). The removal of the water, toluene and sulfate takes place after completion of the isocyanate polyaddition according to the process according to the invention by distillation and filtration.

The dispersions produced by the process according to the invention can be converted as "modified" low or high molecular weight polyhydroxyl compounds in a manner known per se together with polyisocyanates of the type mentioned above, optionally together with unmodified polyhydroxyl compounds or polyamines, hydrazines or hydrazides of the type mentioned above as chain extenders and optionally blowing agents, catalysts and other additives to polyurethane plastics with improved mechanical properties. Examples include foams, elastomers, homogeneous and porous top coats and coatings, paints and thermoplastically processable polyurethanes. In addition, the process products can also be used as such or after conversion with an excess of polyisocyanate to form "modified" prepolymers to produce aqueous polyurethane dispersions using known processes.

The particle size of the dispersed polyaddition products is also of crucial importance for the property improvements that the process products according to the invention bring about in the polyurethane plastics produced from them (especially improved compression hardness). For example, when using polyether dispersions as starting material for the production of polyurethane foams, the diameter of the filler particles must be well below the cell web dimensions (20-50 μm). In polyurethane coatings, the particles must also be so small that even very thin applications produce uniform coatings with a smooth surface.

The process according to the invention advantageously produces dispersions whose particle size of 0.01-5 μηι, or preferably 0.1-1 μιλ, corresponds well to the application-related requirements.

The following examples illustrate the process according to the invention. Unless otherwise stated, numbers are to be understood as parts by weight or percentages by weight.

Comparison example la and examples Ib and Ic

20% polyhydrazodicarbonamide dispersion in trifunctional polyether;

V NH '"7 "~

Recipe:

80.0 parts by weight of a trimethylolpropane-based polyether made from propylene oxide and ethylene oxide with an OH number of 34 and approximately 80% primary OH groups (hereinafter referred to as “polyether I”) as a dispersant;

16.9 parts by weight of toluene diisocyanate

(Isomer mixture 2,4-: 2,6- = 80:20; hereinafter referred to as “T 80”);

3.1 parts by weight of hydrazine (as hydrate 99°/big, if necessary diluted with water).

Water content: see Table I.

General working method

The dispersant preheated to 70°C and the hydrazine hydrate diluted with water are mixed in a kettle stirrer with reflux condenser

and heated to 80°C while stirring. Then the diisocyanate mixture is quickly added to the stirring cone. The polyaddition begins immediately with the water boiling vigorously under reflux. The temperature after the diisocyanate has been added is reduced to 60–80°C within 20–30 minutes (if necessary by cooling) and the water is distilled off under reduced pressure. Towards the end, the temperature is allowed to rise to 90–120°C until no water is released.

&iacgr;&ogr; more passes over and is filtered, if the viscosity allows it (examples l and Ic), through a &Igr;&Ogr;&Ogr;-&mgr;&pgr;&ig; sieve.

Table 1

Example wt.% water, based on

Reaction dispersant solid

mixed (incl.

Water)

Dispersion
(anhydrous)

Viscosity 25°C [cp]

20%

Look

la (comparison) 4.8
Ib 7,9

6.3 10.7

25.2 42.7

Ic 11.3 16.0 64.0

*) Diluted to 10% solids content by addition of Polyether I 5.0
8.5

12.8

268000
2700

2315
1350*)

paste

fine-particle dispersion

fine-particle dispersion

Comparison example Id

If example la is repeated, but without the addition of water, the reaction mixture will turn into a paste during the addition of the diisocyanate under otherwise identical conditions.

Comparison example Ie

If example la is repeated with 50 wt.% water in the reaction mixture, phase separation occurs; when the water is removed, pasting occurs.

Example 2

35

45

40% polyhydrazodicarbonamide dispersion trifunctional polyether

in polyether I diluted to 20 or 10% solids from 1550 or 1050 cP/25°C).

Reaction conditions

In a modification of the procedure of Example 1 a, a 500-l stirred tank is used and the diisocyanate mixture is not introduced into the stirrer cone, but into the lower third of the tank with low inlet pressure.

Comparison test

Without the addition of water, the reaction mixture becomes pasty and the stirrer stops before the entire amount of diisocyanate has been added.

50

The recipe is analogous to example la, but adjusted to 40% solids content.

At a water content of 20 wt.-%, based on the reaction mixture including water (that is 41.5 or 62 or 25 wt.%, based on dispersant or solid or anhydrous dispersion), a very finely divided dispersion (0.3-2 μπα) with a viscosity of 12 800 cP/25 ^e C at ¹ a residual water content of 0.4% (with additional

Ho-CH ₂ -Ch ₂ -N-CH ₂ -CH ₂ -OH

55

60

Example 3

20% modified polyhydrazodicarbonamide dispersion in trifunctional polyether; index = 100

Recipe:

80.0 parts by weight of polyether I;
14.3 parts by weight of diisocyanate T80;
3.2 parts by weight of diol urea ether

CO-NH-(CH ₂ ) ₆ -NHCO-O-(CH ₂ -CH ₂ -O)J ₅ -C ₄ H ₉

3.5 parts by weight of hydrazine (in the form of 99% hydrazine hydrate; added diluted with water) and a total of 11.9% by weight of water, based on the reaction mixture

65 mixture (= 16.8%, based on dispersant; 67.4%, based on solids; 13.5%, based on anhydrous final product).

The procedure is analogous to Example la. However, the diol urea ether is first reacted with an excess of the diisocyanate (number 200) at 100 ^° C, after cooling it is mixed with the remaining amount of diisocyanate T 80 and introduced into the receiver in this form.

The resulting very finely divided polyol dispersion has a residual water content of 0.3 wt.% and a viscosity of 2120 cP/25°C

Example 3a Key figure = 100

Recipe:

80.0 parts by weight of a trimethylolpropane-started polyether (polyether II) made from propylene oxide and ethylene oxide (OH number = 35; approx. 70% primary OH groups);

14.3 parts by weight of diisocyanate T 80;

4.4 parts by weight of diethylene glycol;
1.3 parts by weight of hydrazine (as 99% hydrate; diluted with water and added to the initial charge); and a total of

13.7% by weight of water, based on the reaction mixture including water (= 19.8%, based on dispersant; 73.4%, based on solids; 15.9%, based on anhydrous final product).

The procedure is analogous to Example la, but first a prepolymer is prepared from the diethylene glycol and a portion of the diisocyanate (code number 200), then the remaining diisocyanate is added and the diluted prepolymer thus obtained is introduced into the reaction mixture.

The viscosity of the resulting finely divided, 20%, essentially water-free dispersion is 2670cP/25°C.

Example 4

38.3% OH-functional polyhydrazodicarbonamide polyurea dispersion in a linear polyether

35

40

Key figure 1
Key figure 2

NCO

NH + OH

100 10(A = 91

Recipe:
61.7 wt.

31.0 wt.-5.2
Weight-

2.1 wt.-22.3
Weight-

50

&bull;Parts of a linear polypropylene glycol with secondary OH groups (hereinafter referred to as polyether III; OH number = 56);

Parts DiisocyanateT 80;

&bull;Parts hydrazine (as 99% hydrazine hydrate; added diluted with water);

parts ethanolamine; total

·% water, based on reaction mixture including water (= 46.5%, based on

nispergicnmittel: 75.1%. based on solid

substance; 28.7%, based on anhydrous dispersion).

The procedure is analogous to example 2.

The resulting stable polyether dispersion, which contains 0.2% by weight of residual water, has a viscosity of 2460 (680 or 510) cP/25° C at 40% or when diluted with the polyether used to 20 or 10%.

Example 4a

10

If the recipe of Example 4 is modified analogously to Example 3, but the reaction product of the diisocyanate with 3% by weight of the dispersant (based on total solids) is used as the prepolymer, then an even more one-part dispersion with excellent flow properties is obtained compared to Example 4.

Example 5

40%, highly cross-linked polyurea-polyhydrazodicarbonamide dispersion in trifunctional polyether; index = 100

Recipe

60.0 wt.

31.0 wt.

2.9 wt.

-parts polyether I;

-Parts diisocyanate T 80;

&bull;Parts Hydrazine (as diluted with water

Hydrazine hydrate added);
6.1 parts by weight of diethylenetriamine; total
18.9% by weight of water, based on the reaction mixture including water (= 38.9%, based on dispersant; 58.4%, based on solids; 23.3%, based on anhydrous final product).

The stable dispersion prepared analogously to Example 1a has a viscosity of 40 (or 20 or 10)% of 18,500 (3,800 or 2,200) cP/25°C.

Example 6

20% polyhydrazodicarbonamide dispersion in polyester; index = 100

Recipe:

80.0 parts by weight of a polyester made from adipic acid, trimethylolpropane and diethylene glycol (OH number = 56; acid number = 1; hereinafter referred to as polyester ATD);

16.9 parts by weight of diisocyanate T 80;
3.1 parts by weight of hydrazine (added as hydrazine hydrate diluted with water; total
11.3% by weight of water, based on reaction mixture including water (= 16%, based on dispersant; 64%, based on solids: 12.8%, based on anhydrous polyester dispersion).

The procedure is analogous to Example 1a. A stable dispersion is obtained whose viscosity at 20 or 10% solids content is 35,500 or 24,500 cP/25°C. The pure polyester has a viscosity of 21,400 cP/25°C.

Comparison test

If no water is added to the initial mixture before the addition of the diisocyanate, so that only the small amount of water from the undiluted hydrazine hydrate is present, the reaction mixture will completely solidify before the addition of the diisocyanate has been completed.

Example 7

Dispersion in a polyether/polyester mixture
If the solids content of the 38.3%

Dispersion from example 4 by stirring in polyester ATD (viscosity 21400 cP/25°C) to 20 or 10 wt.%, a stable polyether/polyester mixture is obtained with a viscosity of 19 800 or 24 200 cP/25°C

A mixture of pure polyether III and polyester ATD (without dispersed solids), on the other hand, separates into two phases after just a few hours.

Example 8

20% polyurethane dispersion in polyether with secondary OH groups; index - 100

Recipe:

80.0 parts by weight of polyether III;

11.8 parts by weight of diisocyanate T 80;
8.2 parts by weight of N-methyldiethanolamine;
7.0% by weight of water, based on reaction mixture including water (= 9.4%, based on dispersant; 37.5%, based on solids; 7.5%, based on anhydrous dispersion).

- Procedure

Polyether, N-methyldiethanolamine and water are placed in a stirred apparatus at room temperature and the diisocyanate is added slowly while cooling so that the reaction temperature does not exceed 50 ^° C. 60 minutes after the addition of all the isocyanate, the water is distilled off under reduced pressure. Towards the end of the distillation, the temperature can be gradually increased to 90°C.

The viscosity of the stable 20% dispersion thus obtained is 2210 cP/25° C.

35

Comparison test

Under otherwise identical reaction conditions, a dispersion is formed without the addition of water to the reaction mixture, which sediments overnight.

40

Example 9

20% polyhydrazodicarbonamide dispersion in trifunctional polyether

Recipe
80.0 wt.

45

55

-Parts of a polyether started on trimethylolpropane from propylene oxide and ethylene oxide (OH number 28; approx. 80% pi .meric OH groups);

7.1 parts by weight of toluene diisocyanate; (isomer mixture 2.4 to 2.6 = 65:35);

10.2 parts by weight of 4,4'-diphenylmethane diisocyanate;
2.7 parts by weight of hydrazine (as 99% hydrate; added diluted with water); total

13.0% by weight of water, based on reaction mixture including water (= 18.6%, based on dispersant; 74.5%, based on solids; 14.9%, based on anhydrous end product).

Procedure

The polyether is used as a raw polyether suspension containing 10.5% water and 0.5% alkali sulfate and mixed with the hydrazine hydrate. The polyaddition is carried out "in situ" by adding the mixture of the diisocyanates mentioned under the conditions given in Example la. The resulting, largely water-free 20% stable dispersion has a viscosity of 4200 cP/25°C or, after dilution with further (water-free) polyether to 10%, 2100 cF/725°C.

Example 10

The procedure is completely analogous to example 9, however ■instead of pure diphenylmethane diisocyanate, a technical product is used which partly also contains polyisocyanates containing three and four benzene rings. The viscosity of the 20% or 10% stable dispersion is 3200 or 1900 cP/25° C.

The following examples show possible uses for the dispersions according to the invention.

Example 11

100.0 parts by weight of the polyhydrazodicarbonamide polyether dispersion adjusted to 20% solids content according to Example Ic,

3.0 parts by weight water
0.2 parts by weight of triethylenediamine 0.3 parts by weight of 2-dimethylaminoethanol 0.8 parts by weight of a commercially available polysiloxane

Foam stabilizer and 0.22 parts by weight of tin(II) octoate

were mixed together. This mixture was mixed with

24.1 parts by weight of toluene diisocyanate

(65% 2,4- and 35% 2,6-isomer) and 12.0 parts by weight of toluene diisocyanate

(80% 2,4- and 20% 2,6-isomer)

Stirred thoroughly at room temperature. After 8-9 seconds, a creamy reaction mixture was formed, with a rising time of 75 seconds and a setting time of 120 seconds.

The foam obtained showed the following mechanical properties:

Bulk density
tensile strenght
Elongation at break
Compressive strength

according to DIN 53 420 according to DIN 53 571 according to DIN 53 571 according to DIN 53 577

33kg/ ^m3 160KPa 190% 5.3KPa

Indentation test according to ASTM D 1564-71 T

H-value at 25% deformation (N) 290

&EEgr;-value at 65% deformation (N) 540

RH value at 25% deformation (N) 200

(25% RH value/250/o H value) x 100 70%

65% H-value/25% H-value 1.9

Comparison test

The same recipe was used, but instead of the polyhydrazodicarbonamide dispersion, 100 parts by weight of polyether I was used as a dispersant. If the same ratio of NCO/OH groups (index) is maintained, a foam with the same bulk density is obtained, but according to DIN 53 577 it has a compression hardness of only 4.8 KPa.

100.0 parts by weight
5.0 parts by weight

Example 12

the dispersion from Example Ic, water '

0.2 parts by weight of triethylenediamine 0.3 parts by weight of 2-dimethylaminoethanol 1.0 parts by weight of polysiloxane foam stabilizer

and
0.2 parts by weight of tin(II) octoate

were mixed together. This mixture was mixed with

28.55 parts by weight of toluene diisocyanate

Toluene diisocyanate

(650/0 2,4- and 35% 2,6-isomer)

and
28.55 parts by weight of toluene diisocyanate

(80% 2,4- and 20% 2,6-isomeres)

stirred at room temperature. After 6-7 seconds, a creamy reaction mixture was formed, with a rising time of 55 seconds and a setting time of 100 seconds.

The foam obtained showed the following mechanical properties:

10

15

20

Bulk density
tensile strenght
Elongation at break
Compressive strength

according to DIN 53 420 according to DIN 53 571 according to DlN 53 571 according to DIN 53 577

Indentation test according to ASTM D 1564-71 T

&EEgr;-value at 25% deformation
&EEgr;-value at 65% deformation
RH value at 25% deformation
(25% RH-value/25% &EEgr;-value) x 100 65% H-value/25% H-value

24 kg/m ³ 140 KPa 180% 4.1 KPa

130 255 95 73% 2.0

Example 13

100.0 parts by weight of the dispersion from Example Ic adjusted to 10% solids content,

3.0 parts by weight water
0.1 part by weight of triethylenediamine 0.3 part by weight of 2-dimethylaminoethanol 1.0 part by weight of polysiloxane foam stabilizer and

30

35

40

45

0.18 parts by weight of tin(II) octoate

··. jrden mixed together. This mixture with

19.2 parts by weight

became

Toluene diisocyanate

(65% 2.4- and 35% 2,6-isomer and
19.2 parts by weight of toluene diisocyanate

(80% 2,4- and 20% 2,6-isomer)

thoroughly stirred at room temperature. After 10 seconds, a creamy reaction mixture was formed, with a rise time of 102 seconds and a setting time of 180 seconds.

The foam obtained showed the following mechanical properties:

Bulk density according to DIN 53 420 34 kg/m ³

Tensile strength according to DIN 53 571 150KPa

Elongation at break according to DIN 53 571 200%

Compressive strength according to DIN 53 577 5.1 KPa

Indentation test according to ASTM D 1564-71T &EEgr;-value at 25% deformation 275

&EEgr;-value at 65% deformation 510

60

65

RH value at 25% deformation
(25% RH value/25% �EEgr; value) x 100
65% H-value/250/o H-value

180

65%

1.9

Example 14

100.0 parts by weight
5.0 parts by weight
0.1 parts by weight
0.3 parts by weight
U parts by weight
0.2 parts by weight

the dispersion from Example Ic,

Water

Triethylenediamine

2-Dimethylaminoethanol

Polysiloxane foam stabilizer.

Tin(II) octoate

were mixed together. This mixture was

28.85 parts by weight of toluene diisocyanate

(65% 2,4- and 35% 2,6-isomer)

and
28.85 parts by weight of toluene diisocyanate

(80% 2,4- and 20% 2,6-isomer)

Stirred thoroughly at room temperature. After 8 seconds, a creamy reaction mixture was formed, with a rising time of 60 seconds and a setting time of 100 seconds.

The foam obtained showed the following mechanical properties:

according to DIN 53 420 23 kg/m ³

according to DIN 53 571 140 KPa

according to DIN 53 571 190%

according to DIN 53 577 3.9 KPa

Bulk density
tensile strenght
Elongation at break
Compressive strength

Indentation test according to ASTM D 1564-71 T

H-value at 25% deformation 110

H-value at 65% deformation 235

RH value at 25% deformation 80

(25% RH value/25% H value) x 100 72%

65% H-value/25% H-value 1.9

Example 15

100.0 parts by weight of the stable polyurea-polyhydrazodicarbonamide dispersion adjusted to 10% solids content (polyester to polyether = 5:1) according to Example 7

4.0 parts by weight water

0.6 parts by weight of dimethylbenzylamine

0.1 part by weight of Sn(II) octoate and

2.0 parts by weight of a commercially available polysiloxane foam stabilizer

were mixed together. This mixture was mixed with

52.5 parts by weight of diisocyanate T 80
at room temperature. After 10 seconds a creamy reaction mixture was formed, the rising time of which was 65 seconds and the setting time 125 seconds.

In contrast to the usual closed-cell, pure polyester foams, the resulting foam has open cells and is suitable as a filter material due to its uniform, very fine cell structure.

If the example is repeated with a mixture of pure polyester and polyether without dispersed polyurethane solids in the same mixing ratio, one obtains an open-cell foam,

25

but with much larger cells, some of whose cell membranes are still present.

As already mentioned, the mixture of pure polyester and polyether is not stable in storage. It separates into two phases within a short time when left to stand at room temperature.

Example 16
Homogeneous polyurethane sheeting

a) Preparation of a prepolymer

89.7 parts by weight of the 40% polyether dispersion from Example 2 are reacted at 100&mdash; HO ⁰ C with 10.3 parts by weight of diisocyanate T 80 until the free isocyanate content is 3.0% by weight. The prepolymer thus obtained has a viscosity of 24,800 cP/25°C and is stable at room temperature. |

b) Production of a polyurethane elastomer ^r

The prepolymer is treated with 0.2 wt.% tin(II)-octo-

at and with the help of a doctor blade in a ff

A layer thickness of 500 μια is applied to a glass plate. After heating at 110–130° C (30–60 min.), a film resistant to organic solvents with good strength properties is obtained.

c) Solvent-free coating

If the same prepolymer is mixed with 5 equivalents of «

lent-% deficit of ethanolamine and carries the I

The mixture is applied to a release paper using a doctor blade in a thickness of 500 μm using the reversal process. The elastomer that forms solidifies within a few seconds in an infrared channel. A textile substrate is applied to the still sticky layer using the reverse process.

laminated with light pressure and the polyaddition reaction ₄₀ I

tion was completed in a heating channel with a temperature decreasing from 180 to 120 ⁰ C.

The coated fabric is very resistant to abrasion and organic solvents.

45 comparison tests

If a prepolymer containing 3% free isocyanate groups is prepared from the pure dispersant (polyether I) analogously to Example 16, this is heated with the catalyst under otherwise identical conditions and cooled to room temperature, only a transparent, sticky elastomer mass is formed without any structural strength, which cannot be separated from the substrate.

The use of ethanolamine leads to a similar, sticky product

Claims (8)

Patent claims: 1. Process for the »in situ« production of stable dispersions of polyisocyanate polyaddition products in compounds containing hydroxyl groups as dispersants by reacting (1.) organic polyisocyanates with at least difunctional compounds containing primary and/or secondary amino groups with a molecular weight of 60-10000 and/or Hydrazines with a molecular weight of 32-500 and/or Hydrazides with a molecular weight of 90-10000 and/or at least difunctional primary hydroxyl group containing compounds with a molecular weight of 62-400 in
Compounds containing at least one hydroxyl group with a molecular weight of 62-16000 where the compounds of group (3) have secondary hydroxyl groups if compounds of group (2) are those with primary hydroxyl groups, characterized in that the reaction components are reacted in the presence of 7-35% by weight of water, or when using strongly hydrophilic alcohols in the presence of 4-35% by weight of water, based on the reaction mixture (including water), and optionally the water is subsequently removed in a manner known per se. 2. Process according to claim 1, characterized in that monoisocyanates and/or primary or secondary monoamines and/or monohydrazides are used as reaction components (1 or 2). 3. Process according to claim 1 and 2, characterized in that inert organic solvents are used to reduce the viscosity of the reaction mixture. 4. Process according to claims 1 to 3 ₂ , characterized in that an unpurified crude polyether containing water, organic solvents and alkali salts is used as the dispersant, as is obtained in the industrial production of polyether polyols. 5. Process according to claim 1 to 4 _A , characterized in that the reaction of the components (1 and 2) in the dispersant (3) takes place discontinuously in tank stirring apparatus with reflux condenser. 6. Dispersions of polyureas and/or polyhydrazodicarbonamides containing 10 to 60% by weight of solids in hydroxyl compounds having a molecular weight between 62 and 400. 7. Dispersions of polyureas and/or polyhydrazodicarbonamides in hydroxyl compounds containing 10 to 60% by weight of solids, which consist of more than 30% by weight of polyesters and/or polyesteramides and/or polycarbonates with a molecular weight between 400 and 12,000. 8. Use of the dispersions of polyisocyanate polyaddition products in hydroxyl-containing compounds obtainable according to claims 1 to 5 as starting components for the io